Kerry said on Friday Washington was evaluating whether it was worth continuing its role in Middle East peace talks.

In an attempt to refute reports that the White House sought to distance itself from US Secretary of State John Kerry’s thus-far unsuccessful efforts to mediate peace talks between Israel and the Palestinians, the administration publicly backed its top diplomat on Saturday.

The New York Times cited a senior White House official who quoted President Barack Obama as offering unqualified support for Kerry, who has been maligned by critics in the press and in the Israeli government for what is perceived to be his readiness to take on a lost cause.

“I see a lot of senior officials quoted about Kerry and Middle East peace,” a White House aide quoted Obama as saying, according to the Times. “But I’m the most senior official, and I have nothing but admiration for how John has handled this.”

Reuters is reporting that Israeli and Palestinian negotiators are due in Washington on Sunday to meet with Martin Indyk, Kerry's envoy to the peace talks.

Kerry said on Friday Washington was evaluating whether it was worth continuing its role in Middle East peace talks, signaling his patience with the Israelis and Palestinians was running out.

There was a limit to US efforts if the parties themselves were unwilling to move forward, Kerry said during a visit to Morocco after a week of setbacks.

"This is not an open-ended effort, it never has been. It is reality check time, and we intend to evaluate precisely what the next steps will be," Kerry said, adding he would return to Washington on Friday to consult with the Obama administration.

White House spokesman Josh Earnest acknowledged that President Barack Obama shared Kerry's frustration over "unhelpful" actions by both sides and the two men would discuss the path forward in the eight-month-old talks after the secretary of state's return to Washington.

Kerry's decision to declare a time-out could be an attempt to pressure Israel and the Palestinians to soften their entrenched positions but, should that fail, it might mark the beginning of the end for his signature diplomatic initiative.

By stepping away for now, Kerry is reminding the parties that he can ill-afford to focus endlessly on a fruitless Middle East peace process when other pressing international issues like the crisis in Ukraine demand more of this attention.